Did some research online and found it was a common issue, and what works for most people is just to power the device off and back on again, and that worked for me.
My theory is that since I did the upgrade while it was connected to the accessory, iOS left some kind of flag turned on in memory that it was already connected to an accessory and now it thought I was connecting a 2nd one (it was basically locked to a "ghost" image of the same accessory).
I hate that they now force you to upgrade these things. Even with auto update disabled it still downloads the upgrade and then nags you. I only use it for music, podcasts and and Audible - it's not a phone and I don't need or want any system upgrades (take note Win10 haters, Apple has been doing this longer than MS has).
I did find this tip which I'll try next time a get an upgrade forced on me:
Yes there is a way to disable it. First let me explain why you are getting that notification. Even if you have automatic updates turned off, the new IOS update still downloads to your phone and iPad. It is already in your phone and iPad right now waiting for you to completely install it. It is not installed but it is sitting there in your phone and iPad waiting for you to click on it to install. So what you must do is the following:
Click on the Setting icon. Then click on General. click on Storage & iCloud usage. It might just say Storage on your device. When the next page pops up you will see at the top the word Storage. Under it you will see Manage Storage. Click on it and wait till the list is fully populated. Depending on how many apps you have this can take a couple of seconds to about half a minute. Look through this list till you see the new iOS update. Delete it. Then your pop up notice should go away. Don't worry about loosing the update. You can always get it later in the future. If in the future you get the pop up again, then that means Apple has again downloaded it to your phone or iPad without your permission. Simply do the above all over again to delete it and get rid of the new pop up. This is the only way to get rid of the pop up without installing it.
